New pyrazolone derivatives



United S P m 2,731,413 NEW PYRAzoLoNnnEmvArrvnsj William Taub, Rehovoth, Israel, assignor to J. R. Geigy A. G., Basel, Switzerland, :1 Swiss firm No Drawing. Application August 9, 1954, a Serial No. 448,73 5 C a ms Pr ppli fian. sw m Augusta, 1 53 gen; can=be converted into the corresponding 4-alkyl comwherein R1. represents hydrogen, a. lowsmolecular aliphatic hydrok.

carbon radical, theramino dialkylamino group, a

R2 represents. a low. molecular aliphatic .hydrocarbon radical, Ra represents hydrogen, a low, molecular alkyl group or an alkoxy group,

are new. It has been found that these compounds have an excellent analgetic, antipyretic and antiphlogistic action and, in addition, some of themare valuable starting products for the production of other compounds in of pharmacological interest.

group, or an alleylamino =or The new compounds canbe produced by condensingra reactive derivative of a cyclopropanes carbonyl acetic acid ofthegeneralformula: t r b with an aryl hydrazine of the general formula:

wherein R1? represents hydrogenoor 1a low molecular aliphatic 1 hy;

drocarbon radical, M X represents a radicalwhich phenylamino group, and,

R: has the meaning given-above, v to form a compound of the general formula:

Q on-o c ai H v g l a o i HNw or l is v pl taotf ini l re s o a such asrfor example, analkoiry radical, theamino or,

. 2 If desired, then compounds: wherein R1 represents hydropounds by condensation and simultaneous or. later reductionwitha low molecular aliphaticoxo compound. After orrinsteadof: the introduction. of an alkyl radical R1, an

alkylor; alkenyl radical R2 is introduced by treatmentwith an alkylating agent and' if desired, compounds in which R1" represents hydrogen can be converted by meth ods known per se intothe corresponding 4-amino, 4-alkylamino or4-dialkylamino compounds. 1 i

The condensation of cyclopropane carbonyl acetic acid esters: of the general Formula II with aryl'hydrazines of the general Formula llI to fornrthepyrazolone derivatives of:the general. FormulalV canbeperformediina mannerw analogous to thecondensation of' aeetoaceticacid estersrwith arylhydrazines. 1 r

If .cyclopropane carbonyliacetic aeidderivativesof the general formular a i. e. compounds in which R1 ishydrogen, are usecl as starting materials and are reacted witharyl hydrazines of the general FormulaIII and then an alkyl or alkenyl radicalRz is introduced, then compounds, unsubstituted in. thei4.-position, of 'thegeneral formula A's cyclopropanehcarbonyl acetic acid estersof the general. Formula II, cyclopropane carbonyl acetic acid'ethyl and methyl esters as wellas wcyclopropane carbonyl-'propicnic acid ethyl ester (coacyclopropane carbonyl methylacetic acidethyluester), -butyric acid ethyl ester, -valeric,, acid ethyl ester, isovalericw acid ethyl ester, -caproic acid ethyl ester and: -allylr acetic acid ethyl estervcambe used asrstarting materials, They: are produced easily by reacting the corresponding aliphatic halogen: compounds with the: sodiumtcompound. of r the cyclo propane; carbonyl acetic acid, ethyl ester. In addition to phenyl hydrazine, e. g. 2.-methyl, B-methyl, 4-methyl, 244- dimethyl, 2.5-.climethyl, 4.-ethyl,r.4-.tert. butyl, 2-methoxy, B-methoxy, 4-methoxy, 2-ethoxy andx4-ethoxy-phenyl hydraz ine, can be used as aryluhydrazines of the general Formula III. A r

Thereaction of the two components. often occurs already at, room temperature if a suitable solvent is added'at the same time, e. g. methanol, ethanol or ethanol containw ing water. The reaction can be completed by boiling the solvent under reflux.

On completion of the closure of the. ring, if desired an alkyl radical R1 can be introduced by condensing a compound of the general Formula IV with a low molecular aliphatic oxo compound, preferably a ketone, such as, e. g. acetone, methyl ethyl ketone or diethyl ketone and then hydrogenating either simultaneously or later.

The alkyl or alkenyl radical R2 is introduced by methods known per se by reacting an alkylation agent such as e, g. dimethyl or diethyl sulphate, methyl iodide, ethyl,

propyl "vinyl: mm in-1 hepr sen e absence-of; an .inertbrean ent, withvr onden at onprod. not; w h ,Isensr l F ula I n he prim rr quaternary Patented Jan. 17, 1956 reaction product obtained is converted into the desired l-aryl-2-alkyl-3-cyclopropyl-pyrazole-S-one by heating with caustic soda solution. The tertiary compound can also" be produced directly however, by treating a compound of the general Formula IV with an alkylating agent in the presence of an acid binding'agent, e. gjwith dimethyl sulphate or diethyl sulphate in caustic soda solution. The two modifications ot' the process differ, therefore, not in the type of reactants used but only in the order in'which they are used; thus first the alkylating agent and then a basic substance or both at the same time are reacted with a compound of the general Formula IV.

To introduce basic radicals in the 4-position, compounds according to Formula V can be converted by methods known per se into their 4-nitrosoor 4-nitro compounds and these latter can be converted into the 4- amino compounds or into the 4alkylamino compounds or into the '4-dialkylamino compoundsby reduction, if desired in the presence of an aliphatic ketone or aldehyde. If desiredxanyihydrogen atoms present in the amino or alkylamino group can be replaced by alkyl radicals..- 1::

The nitroso group can be introduced,-e. g. by means of nitrous acid, i. e. by means of alkali nitrites in the presence of acid, or by means of'alkyfnitrites such as e. g. amyl nitrite. a I

Below aregiven in'more detail the most important mod- 5 ificationsof the process defined above after the nitroso or nitro group has been introduced.

The'4-nitroso or 4-nitro compounds can be'converted into the 4-amino compounds by means of reducing agents and these amino compounds, if desired can be monoor di-alkylated. Zinc and acetic acid, or catalytically activated hydrogen for example can be used as reducing agents. Platinum or barium sulphate or nickel and cobalt catalysts for example are suitable as catalysts. Suitable alkylating agents are, e. g. alkyl halides, dialkyl sulphates, aryl sulphonic acid alkyl esters as well as formaldehyde in the presence of formic acid. The monoalkylation can also be performed in two steps by first converting the primary 4-amino compounds with aliphatic carbonyl compounds into the 4-alkylidene amino compounds and then treating these latter with reducing agents.

derivatives are then converted into basic compounds corresponding to Formula I.

The following examples serve to further illustrate the invention. Parts are given as parts by weight and their relationship to parts by volume is as that of grammes to cubic centimetres. The temperatures are given in degrees centigrade.

7 EXAMPLE 1 1phenyl-3-cyclopropyl-pyrazole-5-one upon the l-phenyl-3-cyclopropyl-pyrazole-5-one formed crystallises out.. After recrystallisation from methanol, the

product i'nelts at 115. e V

EXAMPLE 2 1-phenyl-2-methyl=3-cyclopropyl pyrazoled-one 200 parts (1 mol) of. 1 .phcny1 3 cyclopropylpyrazole-5-one are heated 'to about 95 on the water bath with 135 parts (1.07 .mol) of dimethyl sulphate. When the reaction has started, the temperature of the reaction mass rises to about 130140 and it is kept at about If sodium bisnlphite is used as reducing agent'for the 4-nitroso compound, then the 4-sulphamino compounds are obtained directly as reaction products and these can be-monoor dialkylated directly; the sulphamino group is then split oflE in another reaction, i. e. if this has not already occurred in the reaction with the alkylating agent.

If the 4-nitroso .or 4nitro derivatives are reduced in the presence .of aliphatic aldehydes, the 4-dimethylamino compounds for example are easily obtained if the reduction is performed with catalytically activated hydrogen inthe presence of formaldehyde. 'If another aliphatic aldehydeor a ketoneis used, both monoalkylamino and also dialkylamino' comp'oundscan .be obtained. V

A further method for the production of compounds of the general Formula I wherein R1 represents an'amino group, an alkylamino group or a dialkylamino group, consists in converting the l-'aryl-3-cyclopropyl-5-pyrazclones of the general Formula V into the 4-bromo derivatives of the general formula:

y reacting that: with molar amounts of prem se and treating thereaction products with water. In this formula R: and Rs ha've the meanings given above. These bromo' 140 for 3-4 hours by heating on the oil bath. The product, cooled to about ,is dissolved in 400 parts by volume of water at 70 and then boiled for 6-8 hours. 400 parts by volume-of NaOH 33% are added to the cooled ".solution and the whole is heated at for 4 hours while stirring. After cooling,.the solidified product is taken up in benzene and after distilling under reduced pressure if necessary, itisr'ecrystallised from isopropanol. M. P.

EXAMPLE '3 .1qphenyl-Z methyl-3cycl0propyl-4-isopropylpyrazoIe-S-one Ifin the process according to Example 1, cyclopropane carbonyl a-i'sopropyl acetic acid ester is used instead of cyclopropane carbonyl acetic acid ester, then l-phenyl-S cyclopropyl-4-isopropyl-pyrazole-S-one is obtained.

.The samefcornpound is obtained by hydrogenating condensation of l-phenyl-3-cyclopropyl-pyrazole-5-one in the presence of acetone.

By methylating according to Example 2, l-phenyl-Z- methyl-3-cyclopropylJ-isdproyl-pyrzizole-5-one is obtained therefrom. M. P. 108.

' EXAMPLE 4 J (p methyl phenyl).---2 methyl- 3 cyclopropylpyrazole 5 one and 1 (m methoxy phenyl) 2- "rnethyl 3 cycloproppyl pyrazole 5 one 156 partsof cyclopropane carbonyl acetic acid ethyl 'este'r'a'nd l22'parts of p-methylphenyl hydrazine in parts by volume of 96% alcohol are boiled under reflux for 6 hours. On cooling, l-(p-methyl-phenyl)-3-cyclopropyl-pyrazole-5-one crystallises out. After rescrystallisation from ethanol it melts at 1401-141".

The 2-methyl compound is obtained by methylation 1-phenyl-2-methyld-cycI0propyl-4-amino-pyraz0le-5one 214 parts (1 mol) of l-phenyl-2-methyl-3-cyclopropyl- 75 pyraz ole-5-one are dissolved in 500 parts of water and 700 parts by volume of acetic acid and the nitroso group is introduced at 5 with 70 parts of sodium nitrite dissolved in 140 parts of water.

After filtering under suction and washing with distilled water, the nitroso compound is obtained which melts after recrystallization from diluted alcohol at 195 243 parts (1 mol) of l-phenyl-2-rnethyl-3-cyclopropyl- 4-nitroso-pyrazole-5-one are added to a solution of 350 parts of sodium bisulphite (100%) and 125 parts of caustic soda solution in 1200 parts of water. The temperature of the solution rises to about 50'. After about 4 hours, the solution is slowly brought to the boil and boiled for 45 minutes. After cooling, a solution of 75 parts of sulphuric acid in 150 parts of water are carefully added and the reaction liquid is brought to the boil under the introduction of air for 30 minutes. After cooling, the amine formed is liberated by an excess of 33% caustic soda solution and taken up in benzene. On evaporating oif the solvent, the raw product is recrystallised from benzene-ligroin. M. P. 125.

EXAMPLE 6 1-phanyl-2-methyl-3-cyclopropyl-4-dimethylaminopyrazole-S-one 229 parts of 1-phenyl-2-methyl-3-cyclopropyl-4-aminopyrazole-S-one are dissolved in 1000 parts of water and boiled under reflux for 8 hours with 250 parts by volume of 30% formaldehyde and 345 parts of 100% formic acid. After cooling, an excess of 33% caustic soda solution is added to the solution and the amine formed is taken up in toluene.

After evaporating off the toluene, the raw product which remains is recrystallised from ligroin. M. P. 94.

EXAMPLE 7 1 -phenyl-3-cycl0pr0pyl-4-allyl-pyrazole-S-one parts by volume of alcohol (96%) are added to 19.8 parts of cyclopropane carbonyl-a-allyl acetic acid ethyl ester (B. R25 135, produced from the sodium compound of cyclopropane carbonyl acetic acid ethyl ester and allyl bromide) and 10.8 parts of phenyl hydrazine and the whole is boiled under reflux for 6 hours. The alcohol is then evaporated oil and the residue is distilled in a high vacuum. 1-pheny1-3-cyclopropy1-4-allyl-pyrazole-5- one passes over at 148-151 under 0.006 mm. pressure.

1-pheny1-2-methy1-3-cyclopropyl-4-allyl-pyrazole-5 one is obtained therefrom by methylation analogous to Example 2.

EXAMPLE 8 1-phenyl-Z-ally[-3-cycl0propyl-pyrazOle-S-one 20 parts of l-phenyl-3-cyclopropyl-pyrazole-S-one are heated for 5 hours at 150 in a sealed tube with 13.5 parts of allyl bromide and 200 parts by volume of henzene. After cooling, the substance which is insoluble in benzene is taken up in water, the aqueous solution is made alkaline and the precipitated product is taken up in ether.

After evaporating off the ether, the residue is distilled off in high vacuum.

What I claim is:

1. A pyrazolone derivative of the general formula:

CE: lCH-(iJzC-Ri a N O References Cited in the file of this patent FOREIGN PATENTS Switzerland Sept. 16, 1927 Switzerland Apr. 2, 1928 OTHER REFERENCES Wahl et a1.: Chem. Abstracts, vol. 3, p. 167 (1909). 

1. A PYRAZOLONE DERIVATIVE OF THE GENERAL FORMULA: 